A vehicle electrical system is already known which includes a vehicle battery, loads and a starter. The vehicle battery is charged in vehicle operation by a generator which is regulated by a voltage regulator. The voltage regulator is connected to the engine control unit of the vehicle.
In recent years, the proportion of the generator in the total torque of the vehicle is rising ever more rapidly. In order to be able to control the idling behavior of the vehicle, the generator is included in the consideration of a torque model of the engine control. For this purpose, for example, the current torque of the generator is calculated by using characteristics maps stored in the engine control. In order to be able to carry out this calculation it is necessary to know the type and thus the size of the generator. In vehicles that have a regulator having a digital interface, this information about the type of generator is supplied to the control unit via the mentioned digital interface.
In vehicles that have a regulator without a digital interface and in which the control unit does not know the type of generator, it is known to use an average value regarding the generator types used in an application for purposes of calculating the current torque of the generator. The result obtained is accordingly imprecise.
A device is known from German Published Patent Application No. 199 49 031 for automatically detecting the generator type of a motor vehicle. This known device has a generator, which is connected via an interface to a control unit, and a battery. The control unit contains a memory in which data of different generator types are stored. Furthermore, the control unit is configured in such a way that by switching an electrical load on and off the voltage characteristic at the generator can be detected and the generator type can be determined by comparison with the stored data.